auto

[Frits van Bommel]

Bill Baxter wrote:
> Lacking any particular extenuating circumstances, I agree that that 
> making types explicit is better than using auto.  But auto makes sense when
[list]

How about:
6) When the actual type may change later, and you want to make sure the 
variable is of the right type?

I've often found this to be very useful, especially since some implicit 
conversions can change the value (e.g. long -> int, signed/unsigned).